Foraging mode constrains the evolution of cephalic horns in lizards and snakes

Federico Banfi, Shai Meiri, Richard Shine, Raoul Van Damme, Simon Baeckens

Research output: Contribution to journalArticlepeer-review


A phylogenetically diverse minority of snake and lizard species exhibit rostral and ocular appendages that substantially modify the shape of their heads. These cephalic horns have evolved multiple times in diverse squamate lineages, enabling comparative tests of hypotheses on the benefits and costs of these distinctive traits. Here, we demonstrate correlated evolution between the occurrence of horns and foraging mode. We argue that although horns may be beneficial for various functions (e.g. camouflage, defence) in animals that move infrequently, they make active foragers more conspicuous to prey and predators, and hence are maladaptive. We therefore expected horns to be more common in species that ambush prey (entailing low movement rates) rather than in actively searching (frequently moving) species. Consistent with that hypothesis, our phylogenetic comparative analysis of published data on 1939 species reveals that cephalic horns occur almost exclusively in sit-and-wait predators. This finding underlines how foraging mode constrains the morphology of squamates and provides a compelling starting point for similar studies in other animal groups.

Original languageEnglish
Article number20230395
JournalBiology Letters
Issue number11
StatePublished - 22 Nov 2023


  • adaptation
  • cephalic appendages
  • morphology
  • phylogenetic comparative methods
  • squamates

All Science Journal Classification (ASJC) codes

  • Agricultural and Biological Sciences (miscellaneous)
  • General Agricultural and Biological Sciences


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